In one of the biggest surprises in women’s tennis since the French Open, tournament favorite Serena Williams was stunned this evening by fellow American Sloane Stephens 36, 75, 64 in the quarterfinals at the Australian Open.

The 19-year-old Stephens was aided by Serena who was visibly battling back spasms. Stephens had never been to a Grand Slam quarterfinal before and now the new star is into the semifinals where tomorrow she’ll meet top seed and defending champion Victoria Azarenka.

Serena, who was going for a record sixth tournament title, has now lost before the semifinals the last two years at the Australian Open. The 31-year-old had won 20 straight matches until today and the last two Grand Slams.

Serena started the tournament rolling her right ankle in the first match but recovered to find her form in the later rounds. Then today Serena seemed to be in control up a set with a break but the back broke down.

Here’s her presser:

Q. Your emotions, where are you at at the moment?
SERENA WILLIAMS: I’m here in the press conference. I don’t know. I haven’t really thought about it too much.

Q. How is the physical injury? How is the back?
SERENA WILLIAMS: It’s fine. You know, just nothing. I think everyone at this stage in the locker room has something wrong with them, so it’s fine.
There’s no excuse there.

Q. You were serving at about 130 kilometer an hour after the back problem. What exactly happened? Was it tight?
SERENA WILLIAMS: Well, a few days ago it just got really tight and I had no rotation on it. I went for this dropshot in the second set and it just locked up on me, so…
I think that it just I couldn’t really rotate after that, which I guess is normal. I don’t know.

Q. That point where it happened, can you talk us through that moment.
SERENA WILLIAMS: Well, I was running to the net for a dropshot. As I went to hit it, it was on the backhand. I even screamed on the court. I was like, Ahh. I totally locked up after that. It was just like it was a little painful.
But, I mean, it’s okay. It was what it was.

Q. When you went off court, what sort of treatment did you have? Did you take any antiinflammatories?
SERENA WILLIAMS: Well, there’s only so much you can do for that. Not too much you can do. Just tried to have it loosened up a little bit. I’m always on antiinflams for my ankle, so you can’t do too much more.

Q. Did it feel better when you came back on? Were you freer?
SERENA WILLIAMS: No. It was still tough. It’s hard to rotate to the backhand. It was giving me trouble. But it was fine. I think my opponent played well and was able to do a really good job.

Q. The microphones on court picked up you saying this has been the worst two weeks. What did you mean by that?
SERENA WILLIAMS: I’ve had a tough two weeks between the ankle, which is like this big every day, and my back, which started hurting. A lot of stuff, so…
It was what it was.

Q. Is it the worst couple weeks you’ve had at a Grand Slam?
SERENA WILLIAMS: For a Grand Slam, absolutely. Absolutely. Oh, my gosh, I’m almost relieved that it’s over because there’s only so much I felt I could do. I was unaware the microphones picked that up.
But, oh my gosh, it’s been a little difficult. I’ve been thrown a lot of balls these two weeks.

Q. Did you ever think about retiring at any point?
SERENA WILLIAMS: Doug, are you kidding me? I’m not retiring.
Oh, you mean, retiring in the match (laughter). Oh, I’m sorry. I thought you meant my career. Like, you’re crazy.
Uhm, I mean, I thought about it like for a nanosecond. I mean, it’s a quarterfinal of a Grand Slam. Even if I have to take off in a wheeler before I retire.

Q. Did you get the sense Sloane was freaking out a bit towards the end of the second set, just the drama of it all, the injury and everything else, and it was quite hard for her to push through?
SERENA WILLIAMS: Yeah, I definitely felt like she got a little nervous, which is natural. You know, it’s her first quarterfinal. She had a chance to tie it at one set all.
So I definitely feel like she was, uhm, a little nervous at that point.

Q. Could you tell us what you think of her as a player and how far she’s going to push on from here.
SERENA WILLIAMS: She’s a good player. She runs fast and she gets a lot of balls back. That’s always a plus to have in your career.

Q. What did you think of the quality of the match before you tweaked the back?
SERENA WILLIAMS: I don’t think my level was high. I don’t know how many unforced errors I ended up hitting, but for sure more in one set than I probably did in the whole tournament.
So I think her level was high. But as for my end, I mean, you can tell. You each can say this is definitely not my best match in months.

Q. Obviously your serve speed went way down when you had the injury. You started to work your way back in the match in the third set. How much of that were you fighting yourself and how much were you fighting injury in that third set?
SERENA WILLIAMS: Well, at that point you just have to pretend like nothing’s wrong. You think of worst case scenarios. You know, I just thought, Okay, just pretend nothing’s wrong and just try your best.
That’s what I tried to do. Even tried to hit my serves harder. My legs were fine, so running was fine. Just rotating was a little tough.

Q. Yesterday in the game you also hurt a little bit. I want to know before the game today, what did you think about it? Have you ever worried about your injuries?
SERENA WILLIAMS: About what?

Q. Just think about it, think about the injury and worry about that.
SERENA WILLIAMS: No. I’ve actually been injury free for a while until I got to this tournament, and just fell and had the ankle issues. I think that kind of started everything up the chain because I’m compensating and maybe it made my back hurt.
I don’t think about the injuries during the match so much. I just try to keep going and honestly do the best that I can. And really it’s all I can do for that day.

Q. Did you get some frustrations out with that racquet smash?
SERENA WILLIAMS: Oh, yeah. Did you see it? I even had a wry smile on my lips after that. It made me happy, unfortunately.

Q. You were in Mauritius for some preparation. That is my home town. How did it go there?
SERENA WILLIAMS: It went well. I loved it. I hope I can go back.

Q. You mentioned being relieved, this being a difficult two weeks. It’s been a long time since you’ve lost a match. Does the pressure build up? Does it become more and more difficult to keep it going?
SERENA WILLIAMS: No, I feel no pressure. The buildup of losing a match? I personally don’t like to lose, so the less I lose the better for me. And if that means I have a lot of pressure, that’s fine. It doesn’t bother me.

Q. Do you think she’s quiet in the game?
SERENA WILLIAMS: You think she’s quiet?

Q. In last several games you said, You should grunt. She’s a little bit quiet. Also as a mentor for her she thinks of you as a mentor in the future, will you give her some advice?
SERENA WILLIAMS: Well, honestly I’ve never really given her advice, so…
But she doesn’t grunt. Some people grunt; others don’t. So it is what it is.

Q. You were such a favorite for the tournament. How do you see it now on the women’s side? Who do you see progressing to Saturday?
SERENA WILLIAMS: Well, I think it’s interesting. I think Sloane, she’s in the semis now. That gives anyone a chance.
I think Victoria’s playing well. She’s a fan favorite and she’s defending champ. She handles the pressure really well.
So we’ll see.

Q. Is that No. 1 ranking of big importance to you? If it’s going elsewhere now, does that add to the disappointment or not really?
SERENA WILLIAMS: No, I didn’t think about that so much.
For me, I’m trying for Grand Slams and to win titles, you know, get to 50 titles. Not Grand Slams.
No. 1 is awesome if I get it. Like I said, I think I’ll get there one day. If not, I’ve had it, so it is what it is.
But for me it’s definitely more about doing well in tournaments.